The objective of this research is to determine the effects of dietary zinc deficiency on lymphocyte function during the different stages of development. The inbred mouse will continue to serve as a model system for study. A fairly complete profile of the effect of zinc deficiency on immunity in the young adult mouse has been developed by our laboratory. In the current application, we propose to study the effects of zinc deficiency on lymphopoiesis. To accomplish this, bone marrow stem cells prepared from zinc-deficient mice will be examined for their ability to migrate to, colonize, and proliferate in the lymphatic organs. In addition, the effect of periods of suboptimal zinc on development of immunity during the fetal-neonatal period will be investigated. Preliminary evidence suggests that zinc deficiency during ontogeny does alter lymphocyte development. In addition, pilot studies suggest that immune damage incurred during fetal development may not be fully repairable upon nutritional repletion. Thus determining the immune repair capacity of previously zinc-deficient fetal-neonatal mice will represent an additional area of investigation.